Telephone system.



R. L. QUASS. TLPHONE SYSTEM.

APPLICATION FILED MAY 1. 19m.

Patented Oct. 12, 1915.

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, d. 'u Y Iinarini) STATES PATENT orario-E.

RALPH L.- QUASS, OF NEW YORK, lN. Y., ASS1GNOR TO WESTERN ELECTRIC COMPANY, 'OF YORK, N. Y., A CORPORATION OF ILLINOIS.

, TELEPHONE SYSTEM.'

of which the following is a full, clear, conoise, and exact description.

This invention relates to telephone systems,I and more particularly to systems of the central energy type having the ringing current automatically applied to the called line upon connecting the link conductors with the line conductors.

It is the object of this invention to im-I prove systems of this character and to pro- .vide asystem in which the 'usual click in the calling subscribers ear, lresulting from the closing' through of the talking circuit uponvthe removalof ringing current from the line, is ractically eliminated.

lIn accor ance with a feature ofthis ini vention, means are provided at the central oiice whereby when ringing current is removed from theI line the talking oircuitis closed through very slowly, thereby practithe calling subscriber.

cally eliminating the 'click in the receiver of This invention is illustrated. in the accompanying drawing in which all apparatus is shown in its normal and unactuated 'condition.

system containing one embodiment of this invention and comprising theusual subscribers stations A and' B and a cord circuit .C located at a centralk oflice'for inter- 'connecting the subscribers stations. It is believed that this invention will be fully understood from a description of the opera tion of the system shown in the drawing, and it will be so' described. Supposing subscriber A wishes to converse with subscriber l B, A removes his receiver from the switch hook, thereby completing a circuit from the live pole of battery 5 through the winding of line relay 6, normally closed contact 7 of cut-oil' relay/'8, line wires 9 and 10 and the other normally closed contact 11 of relay 8 to ground. urrent in this path actuates the line relay 6 completing a circuit for the line signal 12. The operator, observing the line signal 12 inserts her answering plug in the jack indicated by the signal 12, and thereby completes a circuit from the live Specication of Letters Patent.

There is" shown in the drawing a telephone Patented Oct. 12, 1915.

Application filed May 1, 1914. ISerial No. 835,749.

pole of battery 13 through supervisory siglnal 14, normally closed contact 15 of relay 16, winding of relay 17, sleeve strand 18 of the c ord circuit; sleeve contact 19 of the answering jack and the winding of cut-o relay 8 rto ground. Current in this path actuates the cut-ofi relay 8, which severs the circuit of the line relay 6, eacing the line signal 12, and actuates the relay 17 connecting the operators telephone set across talking strands 2O and 21 of the cord circuit. The insertion of the answering plug also com* pletes a circuit from one pole of battery 25 through the winding of relay 26, over conductor 27, ring contacts 28 and 29 of the answering plug and jack, line wires 9 and 10, .tip contacts 30 and 31 of the answering jack and plug, conductor 32 to the other pole of battery 25. Current in this path actuates relay 26, placing a low resistance shunt 33 about supervisory signal 14 and preventing its operation. The operator new asks the desired nuinber ofthe calling subscriber. Finding the desired number to be that of subscriber B, the operator touches the tip of the calling plug to the sleeve of a jack corresponding to Bs line to determine the idle or busy condition thereof. If the line tests-idle, the calling plug `is inserted in the jack completing a circuit from the live pole of battery 40, through supervisory signal 41,

vwindingof relay- 16, over conductor 42,/V

sleeve contacts 43 and.44 of the calling plug and the jackand through the winding of cut-o relay 45 to ground. Current in this path actuates cut-od relay 45 cutting line relay 46 from the line conductors 47 and 48, operates the supervisory signal 41, and actuates the relay 16, disconnecting the opera tors telephoneset from the talking strands 20 and 2.1 or' the cord circuit. Actua'ticn oi relay 1 6 also completes a 'circuit from the live pole of battery 49 through the winding of relay 50, normally closed contacts 51 of relay 52, 53 of relay 54 and 55 of relay 56, and normallyopen'contact 57 (now closed) of relay 16 to ground. Current in this path actiiates relay 50, connecting a source of ringing current 60 to the line through relay' 54. ARelay 54 is marginal and will not operate when in series with the usual ringer and condenser at the subscribers station, but will operate when the ringer and condenser are shunted by low resistance.

The path for the ringing current through the called lsubscribers ringer is from 60 through winding of relay 54 over conductor 61, normally open contact 6 2 (now closed) of relay 50, ring contacts 63 and 64 of thecalling plug and the jack, line wire 47, condenser 65, ringer 66, line wire V48, tip contacts 67 and 68 of the jack and calling plug,

i and normally open contact 69 (now closed) point 74, the ringing current finds a second path through condenser 70, normally closed contact 72 of relay 56,conductors73 and 2O .and through winding, 75 of repeating coil 76 to ground. The condenser 70 is of very ldw capacity so that there is only a small portion of the ringing current through the winding 75 of the repeating coil. This current is, however, suiiicient to cause a tone to be repeated back to the calling subscriber, thereby making known to him that the called subscriber is being signaled. It will furthermore be observed that this tone to the calling subscriber does not depend upon the condition of the called subscribers line or substation apparatus, and is, therefore,

capable of being maintained constant so that the calling subscriber may at all times readily distinguish this tone from any other which may be placed upon the linel from time to time. The normally closed contact .7 6 of the'relay 50 may be shunted by a condenser 7 7 of about the same capacity as the condenser so that when the cord circuit is arranged for ringing on arty lines and ringing over the other line the calling subscriber may receive the tone. Y

The called subscriber uponremoving his receiver from the switch hook, closes a path of low resistance for the ringing current, thereby permitting a greater iiow of current through'the relay 54. Relay 54 is thereby actuated, opening-the normal shunt about relay 52, and permitting relay 52 to be actuated by current from battery 49, lock itself up through its normally open contact 78 (now closed) and .short circuit relay 50 which releases and removes ringing current from the line. Actuation-of relay 52 also closes a circuit for relay 56, which in operating locks itself up through its normally open contact 79 (now closed), releases relay 52 and closes its normally open contact 80, completing the talking circuit between subscriber-sA and'B. Relay 56 is made slow acting so that when'it is'energized contact 8O is closed very slowly, thereby eliminating the usual click in the receiver of the calling subscriber. When this contact 80 is closed, supervisory relay 85 is actuated by current from battery 25 over the talking strandsof `the cord circuit and thc line wires and ers A and B restore their respective receivers to the switch hooks, thereby opening the circuits at their respective stations for current from battery 25. Supervisory relays 26 and 85 are thereupon denergiznd, per` mitting the supervisory signals i4 and 41 to be operated. The operator thereupon removes the plugs from the jacks and all apparatus returns to its normal position.

Vhile in this description various batteries have been referred to, it is to be understood that a common battery may be substituted. for all of these and such is'the usual practice. At the central oiiice has been provided a key S6 by means of which the operator may at any time throw her telephone set across the talking strands of the cord circuit and supervise the established connection beltween'the two subscribers.

What is claimed is:

1. A telephone system comprising telephone lines terminating at a central oiice, normally open link conductors thereat for connecting said lines in pairs, means associated with said link conductors for automatically applying ringing current to the called line upon connecting said link conductors therewith, means for automatically removing the ringing current from the lcalled line, and means associated with said link conductors for slowly closing said normally open link conductors after the removal of the ringing current.

2. A telephone system comprising telephone lines terminating at a central office, normally open link conductors thereat for connecting said lines in pairs, means associated with said link conductors for automatically applying ringing current to the called line upon connecting said link conductors therewith, means for automatically removing the ringing current from the called line, and a slow acting relay associated with said link conductors and actuated after the ringing current is removed from the line for closing said normally open link conductors.

8. A telephone system comprising tele-v phone lines terminating in a central oiice, link conductors thereat for connecting said lines in pairs, at least one of said conductors being normally open, means associated with said link conductors for automatically ap-A plying ringing current to the called line upon connection of said link a conductor therewith, means for automatically remov'- ing the ringing current from the called line, and means associated with said link conductors and actuated after removal of the ringing current for closing said normally open link conductor.

4. A vtelephone system comprising telephone lines terminating in a central office,

with said link conductors and actuated afterv removal of the ringing current for closingy said normally open link conductor.

5. A telephone system comprising telephone lines terminating in a central oflce, link conductors thereat for connecting said lines in pairs, at least one of said conductors being normally open, means associated with said link conductors for automatically applying ringing current to' the called line upon connection of said link, conductor therewith, a relay for automatically removing the ringing current from the called line, and an electromagnetic relay associated with said link conductor and energized after re moval of the ringing current for closing said normally open link conductor.

In witness whereof, I hereunto subscribe myV name this 29 day of April, A. D., 1914.

RALPH L. QUASS. Witnesses: A

NANON E. TUTHILL, KATHERINE L, STAHL.

opies of this patent may be obtained for ve cents each, by addressing the Commissioner of latents,

' Walhingtorn, D. C. p 

